Scenic overlook of the Illinois
River Valley and a moraine is
a deposit
of unsorted glacial debris

Long Description

You are on top of the Bloomington
Moraine overlooking the city of Peoria to the west. A moraine is
a deposit
of unsorted glacial debris. Moraines formed when the glacier stopped
advancing and remained stationary for many years. Even though the glacier
may have stopped advancing into new territory, the ice that formed
the glacier’s internal zone of flow continued to move forward
toward the outer edge of the glacial lobe. The ice contained massive
amounts of debris that had been scooped up by the glacial ice as it
spread outward from Canada. The debris that was deposited here ranges
in size from large boulders to clay, depending on how much abrasion
the rocks experienced inside the glacier.

This is one of the more spectacular views attributable to this moraine.
The Illinois River flows from your right to your left. This river drains
about 2/3 of the state of Illinois and is a major tributary to the
Mississippi River. Peoria Lake is to your right. Upper Peoria Lake
is beyond McClugage Bridge in the far distance to your right.

The Bloomington Moraine is really a system of moraines that mark the
boundaries of the Peoria Sublobe of the Lake Michigan Lobe of the Woodfordian
glacier. This moraine is a thick deposit and near Peoria it formed
on top of bedrock cliffs. You are standing on one at this time. The
till is about 40 feet thick and is covered by several feet of loess.

This moraine extends from the Livingston-Ford county boundary in eastern
Illinois, through the Illinois River Valley between Peoria and Princeton,
to DeKalb County in northeastern Illinois.

The Bloomington Moraine overrides the Shelbyville Moraine near Peoria
and marks the western edge of Wisconsinan glaciation in Illinois. The
moraine is responsible for approximately 200 feet of sharp relief along
the Illinois River and an even greater amount along the Green River
in Lee County, east of the city of Rock Island. The prominence of this
moraine gives character to many places in Illinois.

The internal ice of the glacier that built the Bloomington Moraine
flowed forward relatively rapidly. This caused a massive accumulation
of unsorted material. The thickness of the ice sheet in central Illinois
was probably between 200 and 400 feet thick.

Look at McClugage Bridge to your far right. In the vicinity of the
bridge, the Bloomington Moraine once extended across the present river.
Water accumulated behind the moraine and formed Glacial Lake Illinois.
The Moraine collapsed under the weight of the water in the lake. Water
and sediment rushed through the valley that lies in front of you.